1. Field of the Invention
This invention relates to a disc-record player comprising a device for scanning disc-shaped information carriers of mutually different diameters, comprising a frame, a turntable comprising a supporting surface for information carriers having a circumferential edge, a device for moving said information carriers in a loading direction and bringing said information carriers in a well-defined position relative to the turntable, which device comprises at least one positioning member which is movable transversely of the loading direction and is constructed to cooperate with the circumferential edges of said information carriers, a detection unit for detecting the position of said information carriers, which detection unit comprises a sliding member which is movable in said loading direction of said information carriers and in a direction opposite thereto, a guide element which is connected to said positioning member and which cooperates with a guiding edge of the sliding member, and a rotary member which is movable about an axis of rotation and which comprises a detection element constructed for cooperation with the circumferential edges of said information carriers, and a servo element.
The invention also relates to a detection unit for use in the disc-record player.
2. Description of the Related Art
U.S. Pat. No. 4,470,136 (herewith incorporated by reference) discloses a disc-record player comprising a loading mechanism for moving phonograph records of different diameters into and out of the player. The loading mechanism comprises two parallel slidable positioning members each comprising a positioning element for cooperation with the circumferential edge of a disc-record to be positioned. The positioning members are coupled to one another by means of a gear wheel and are movable transversely of the loading direction of the records and in opposite directions relative to one another. The loading mechanism further comprises a slide member, which is movable in the loading direction and which has a profiled guiding edge, and a locking plate which is movable transversely of the record-loading direction. One of the positioning members comprises a pin which cooperates selectively with the guiding edge of the slide member and with the locking plate. The loading mechanism further comprises an arm which is rotatable about a fixed axis of rotation and which has a detection element for cooperation with the circumferential edge of the disc record to be positioned, the rotatable arm comprising a pin engaging a guide slot in the slide member. The mechanism is constructed in such a manner that at the end of the loading movement of a disc record, which record has been centred, an actuator element secured to the locking plate actuates a microswitch to stop the loading movement. In the prior-art disc-record player the device for successively moving the disc records in the loading direction, centring said records and detecting the centred position of said records comprises a comparatively large number of parts and its construction and operation are intricate.